1. Field of the Invention
The present invention relates to a method and apparatus for controlling deflections in the work surfaces of a mechanical press. The method and apparatus of the current invention may be used to alter the deflection in the work surface of, for example, the slide or the bed of a mechanical press. The method and apparatus of the current invention may be employed to alter deflections prior or not prior to machining the work surface of a press member and/or during press operation.
2. Description of the Related Art
Mechanical presses, for example, stamping presses and drawing presses, comprise a frame having a crown and a bed with a slide supported within the frame for motion toward and away from the bed. Such mechanical presses are widely used for stamping and drawing operations and vary substantially in size and available tonnage depending upon the intended use.
Conventional press machines employ a tooling apparatus in the form of a die assembly to shape a workpiece, such as in a stamping or drawing operation. The die assembly particularly includes a lower die attached to the work surface of a non-moveable bed or bolster and an upper die or punch attached to the work surface of a reciprocating slide. The upper and lower dies, which are installed in opposing spaced apart relation to one another, cooperate during press machine operation to mutually engage the workpiece at respective sides thereof to thereby effect the desired forming activity.
Repeated stamping operations of a mechanical press cause deflections in portions of the press. For example, press operation causes deflections in the bed and the slide of the mechanical press. Bed and slide deflections are typically within the range of 0.002" per foot to 0.005" per foot of slide or bed width. In some production environments, such deflections will cause scrapping of stamped product which leads to increased cost and production time.
The working surfaces of the slide and the bed are typically machined to produce substantially uniform work surfaces. Having to re-machine these work surfaces is undesirable due to the necessary press down time and the wear to the work surfaces caused by additional machining. Replacing deflected work surfaces is undesirable due to the necessary press down time and substantial expense.
What is needed in the art is an apparatus and method to minimize the deflection experienced by portions of the mechanical press during press operation. What is additionally needed in the art is an apparatus and a method to monitor deflections experienced during press operation and to provide a means for automatically adjusting deflections during press operation.